Geoscientists have made a groundbreaking discovery about the underside of the North American continent, finding that it is slowly dripping away in blobs of rock. This phenomenon, known as “cratonic thinning,” has been observed for the first time at The University of Texas at Austin.
According to researchers, the craton’s stability and ability to persist for billions of years are being affected by changes within its core. The North China Craton lost its deepest root layer millions of years ago, demonstrating that these old rocks can undergo significant transformations.
The dripping is concentrated over the Midwest region of the United States, but it does not pose an immediate threat to the continent’s stability. Instead, it allows scientists to observe the cratonic thinning process as it occurs. This phenomenon could influence how tectonic plates evolve over time and has implications for understanding how planets like Earth have evolved.
The discovery is significant because it provides insights into the long-term evolution of continents. “This sort of thing is important if we want to understand how a planet has evolved over a long time,” said co-author Thorsten Becker.
Researchers used a computer model developed by Junlin Hua and Stephen Grand to reveal new details about geologic processes happening in the crust and mantle underlying North America. The full-waveform seismic tomographic model created a detailed representation of the important zone between the deep mantle and the shallower lithosphere, allowing scientists to infer that the Farallon Plate is driving the process.
The Farallon Plate has been subducting under North America for about 200 million years, but its current interaction with the craton may be wearing it away from below by redirecting the flow of mantle material and releasing volatile compounds. The researchers believe this process could lead to the eventual cessation of the dripping as the remnants of the tectonic plate sink deeper into the mantle.
The study’s findings highlight the significance of observing geologic processes in action, providing new insights into the dynamic nature of our planet.
Source: https://www.jsg.utexas.edu/news/2025/04/north-america-is-dripping-from-below-geoscientists-discover